Reply to Miller etal. (2013) Substantial agreement on the timing and magnitude of Late Holocene ice cap expansion between east Greenland and the eastern Canadian Arctic: A commentary on Lowell etal. (2013)

摘要

Glaciers are sensitive indicators of climate change. Thus recent warming has led to general recession, producing glacier forefields that yield valuable information on the Little Ice Age and the Medieval Warm Period, as well as on older Holocene climate changes. Such forefields in the Swiss Alps and the Canadian Rockies reveal remains of trees killed during past intervals of glacier expansion. From "kill dates" of overridden trees, former glacier advances can be reconstructed in detail. For example, kill dates of larch trees allowed an advance of Gorner Glacier in the Swiss Alps to be tracked for a distance of 1000 m between 1327 AD and a maximum achieved in 1385 AD just short of the Little Ice Age Hochstand of 1859 AD (Holzhauser, 1995; Holzhauser et al., 2005). The same approach was used at Robson Glacier in the Canadian Rockies to show expansion between 1150 and 1350 AD (Luckman, 1995, 2000); an earlier Holocene advance of Peyto Glacier was tracked by kill dates of overridden trees (Luckman et al., 1993).